SW typically only does fireworks during the summer, and the busy week of Christmas.
They probably added additional shows, because they plan to be busy with spring break. More things to see, better way to spread people out throughout the park.
To the OP, One piece of advice, try to get a day plan for the day. Figure out what shows you want to see, and plan to be at each of the stadiums about 30-45 minutes early. I'd say 30 if you don't care what seat you have, just as long as you have a seat, and 60-45 minutes early if you want "the best seat". This is going to be a busy week, and once the stadiums are full, they don't let you in to see the show. They typically have the show schedule listed on seaworld.com so you can get an idea of which times to be where, and then go see animals/exhibits/rides when show's aren't going on.